Pneumatic or Air Gauging is in use in all branches of Manufacturing to perform Quality Control, of machined parts, to precise dimensional tolerances.
As its name implies, this type of gauging uses the shop air available in all manufacturing plants (50-100 PSI) thru an Air Electric Converter such as this invention, to which an air probe or gauging fixture is connected at its outlet.
The part to be checked for proper tolerances is placed on a fixture which incorporates the nozzle(s) from which the compressed air exits the Air Electric Converter or, in some cases, the air tooling which includes the nozzles is manually inserted in the part to measure its inside diameter.
The distance between the face of the nozzle(s) and the surface of the part being checked, determines the amount of air exiting the Air Electric Converter.
Using 1 or 2 “MASTER” parts of precisely known dimension and placing them alternately on the fixture, the entire gauging system can be calibrated to those values.
At this point, each manufactured part will be compared to the mean value and their deviation from the nominal value logged by the processing equipment or in some automatic gauging systems parts can be sorted by categories including rejects.
Although the principal use of this invention is for dimensional gauging of machined parts, it is suitable for checking or classifying precision orifices and measuring very small diameter thru holes.
In today's world, the possibilities for interfacing with other instruments and computers are numerous and ever changing. Those stated are only representative of what is available today.
The invention could be assembled without the phase locked loop or the analog digital converter.
This invention can incorporate an air filter at the inlet and a shut-off valve to manually or automatically close the air to conserve energy.
The present invention has for principal object to provide a single-piece pneumatic circuit module, thus avoiding the complex plumbing of pneumatic circuit units, available on the market, that generally consist of fixed and adjustable orifices, bourdon tubes, bellows, diaphragms, levers and pivots which introduce parasitical friction and hysteresis, which result in inaccurate measurement of work pieces.
Even the most advanced differential units using direct electrical signal from a solid state sensor relying on back pressure measurements have a very small linear range of operation and require complex tooling. Reference to U.S. Pat. No. 4,550,592.